97b94b8882
Part of https://emqx.atlassian.net/browse/EMQX-9251 This ports part of the Schema Registry app from 4.x to 5.0. Here, only support for Avro is added. Subsequent PRs will follow to add support for other formats.
74 lines
2.9 KiB
Markdown
74 lines
2.9 KiB
Markdown
# EMQX Schema Registry
|
|
|
|
EMQX Schema Registry for managing various of schemas for
|
|
decoding/encoding messages.
|
|
|
|
To use schema in rule engine, a schema name should be passed to the
|
|
SQL functions that decode/encode data, like:
|
|
|
|
```sql
|
|
SELECT
|
|
schema_decode('sensor_notify', payload) as payload
|
|
FROM
|
|
"message.publish"
|
|
WHERE
|
|
topic = 't/1'
|
|
```
|
|
|
|
## Using schema registry with rule engine
|
|
|
|
```
|
|
+---------------------------+
|
|
| |
|
|
Events/Msgs | | Events/Msgs
|
|
--------------------> EMQX |------------------>
|
|
| |
|
|
| |
|
|
+-------------|-------------+
|
|
|
|
|
HOOK |
|
|
|
|
|
+-------------v-------------+ +----------+
|
|
| | Data | |
|
|
| Rule Engine ------------- Backends |
|
|
| | | |
|
|
+------|-------------|------+ +----------+
|
|
|^ |^
|
|
Decode|| ||Encode
|
|
|| ||
|
|
+------v|------------v|-----+
|
|
| |
|
|
| Schema Registry |
|
|
| |
|
|
+---------------------------+
|
|
```
|
|
|
|
## Architecture
|
|
|
|
```
|
|
| |
|
|
Decode | [APIs] | Encode
|
|
| |
|
|
| | [Registry]
|
|
+------v--------------v------+
|
|
REGISTER SCHEMA | |
|
|
INSTANCE | | +--------+
|
|
-------------------> | | |
|
|
[Management APIs] | Schema Registry ------ Schema |
|
|
| | | |
|
|
| | +--------+
|
|
| |
|
|
+----------------------------+
|
|
/ | \
|
|
+---/---+ +---|----+ +---\---+
|
|
| | | | | |
|
|
[Decoders] | Avro | |ProtoBuf| |Others |
|
|
| | | | | |
|
|
+-------+ +--------+ +-------+
|
|
|
|
```
|
|
|
|
- Register schema instance: adds a new instance of a schema of a
|
|
certain type. For example, when the user may have several Avro or
|
|
Protobuf schemas that they wish to use with different data flows.
|